Subtitles and Transcript

David Chalmers

0:11
Right nowyou have a movie playing inside your head.It's an amazing multi-track movie.It has 3D vision and surround soundfor what you're seeing and hearing right now,but that's just the start of it.Your movie has smell and taste and touch.It has a sense of your body,pain, hunger, orgasms.It has emotions,anger and happiness.It has memories, like scenes from your childhoodplaying before you.And it has this constant voiceover narrativein your stream of conscious thinking.At the heart of this movie is youexperiencing all this directly.This movie is your stream of consciousness,the subject of experienceof the mind and the world.

1:22
Consciousness is one of the fundamental factsof human existence.Each of us is conscious.We all have our own inner movie,you and you and you.There's nothing we know about more directly.At least, I know about my consciousness directly.I can't be certain that you guys are conscious.

1:46
Consciousness also is what makes life worth living.If we weren't conscious, nothing in our liveswould have meaning or value.But at the same time, it's the mostmysterious phenomenon in the universe.Why are we conscious?Why do we have these inner movies?Why aren't we just robotswho process all this input,produce all that output,without experiencing the inner movie at all?Right now, nobody knows the answersto those questions.I'm going to suggest that to integrate consciousnessinto science, some radical ideas may be needed.

2:30
Some people say a science of consciousnessis impossible.Science, by its nature, is objective.Consciousness, by its nature, is subjective.So there can never be a science of consciousness.For much of the 20th century, that view held sway.Psychologists studied behavior objectively,neuroscientists studied the brain objectively,and nobody even mentioned consciousness.Even 30 years ago, when TED got started,there was very little scientific workon consciousness.

3:08
Now, about 20 years ago,all that began to change.Neuroscientists like Francis Crickand physicists like Roger Penrosesaid now is the time for scienceto attack consciousness.And since then, there's been a real explosion,a flowering of scientific workon consciousness.And this work has been wonderful. It's been great.But it also has some fundamentallimitations so far.The centerpieceof the science of consciousness in recent yearshas been the search for correlations,correlations between certain areas of the brainand certain states of consciousness.We saw some of this kind of workfrom Nancy Kanwisher and the wonderful workshe presented just a few minutes ago.Now we understand much better, for example,the kinds of brain areas that go along withthe conscious experience of seeing facesor of feeling painor of feeling happy.But this is still a science of correlations.It's not a science of explanations.We know that these brain areasgo along with certain kinds of conscious experience,but we don't know why they do.I like to put this by sayingthat this kind of work from neuroscienceis answering some of the questionswe want answered about consciousness,the questions about what certain brain areas doand what they correlate with.But in a certain sense, those are the easy problems.No knock on the neuroscientists.There are no truly easy
problems with consciousness.But it doesn't address the real mysteryat the core of this subject:why is it that all that physical processing in a brainshould be accompanied by consciousness at all?Why is there this inner subjective movie?Right now, we don't really have a bead on that.

5:12
And you might say,let's just give neuroscience a few years.It'll turn out to be another emergent phenomenonlike traffic jams, like hurricanes,like life, and we'll figure it out.The classical cases of emergenceare all cases of emergent behavior,how a traffic jam behaves,how a hurricane functions,how a living organism reproducesand adapts and metabolizes,all questions about objective functioning.You could apply that to the human brainin explaining some of the behaviorsand the functions of the human brainas emergent phenomena:how we walk, how we talk, how we play chess,all these questions about behavior.But when it comes to consciousness,questions about behaviorare among the easy problems.When it comes to the hard problem,that's the question of why is itthat all this behavioris accompanied by subjective experience?And here, the standard paradigmof emergence,even the standard paradigms of neuroscience,don't really, so far, have that much to say.

6:27
Now, I'm a scientific materialist at heart.I want a scientific theory of consciousnessthat works,and for a long time, I banged my headagainst the walllooking for a theory of consciousnessin purely physical termsthat would work.But I eventually came to the conclusionthat that just didn't work for systematic reasons.It's a long story,but the core idea is just that what you getfrom purely reductionist explanationsin physical terms, in brain-based terms,is stories about the functioning of a system,its structure, its dynamics,the behavior it produces,great for solving the easy problems —how we behave, how we function —but when it comes to subjective experience —why does all this feel like
something from the inside? —that's something fundamentally new,and it's always a further question.So I think we're at a kind of impasse here.We've got this wonderful, great chain of explanation,we're used to it, where physics explains chemistry,chemistry explains biology,biology explains parts of psychology.But consciousnessdoesn't seem to fit into this picture.On the one hand, it's a datumthat we're conscious.On the other hand, we don't know howto accommodate it into our
scientific view of the world.So I think consciousness right nowis a kind of anomaly,one that we need to integrateinto our view of the world, but we don't yet see how.Faced with an anomaly like this,radical ideas may be needed,and I think that we may need one or two ideasthat initially seem crazybefore we can come to grips with consciousnessscientifically.

8:24
Now, there are a few candidatesfor what those crazy ideas might be.My friend Dan Dennett, who's here today, has one.His crazy idea is that there is no hard problemof consciousness.The whole idea of the inner subjective movieinvolves a kind of illusion or confusion.Actually, all we've got to do is explainthe objective functions, the behaviors of the brain,and then we've explained everythingthat needs to be explained.Well I say, more power to him.That's the kind of radical ideathat we need to exploreif you want to have a purely reductionistbrain-based theory of consciousness.At the same time, for me and for many other people,that view is a bit too close to simplydenying the datum of consciousnessto be satisfactory.So I go in a different direction.In the time remaining,I want to explore two crazy ideasthat I think may have some promise.

9:25
The first crazy ideais that consciousness is fundamental.Physicists sometimes take
some aspects of the universeas fundamental building blocks:space and time and mass.They postulate fundamental laws governing them,like the laws of gravity or of quantum mechanics.These fundamental properties and lawsaren't explained in terms of anything more basic.Rather, they're taken as primitive,and you build up the world from there.Now sometimes, the list of fundamentals expands.In the 19th century, Maxwell figured outthat you can't explain electromagnetic phenomenain terms of the existing fundamentals —space, time, mass, Newton's laws —so he postulated fundamental lawsof electromagnetismand postulated electric chargeas a fundamental elementthat those laws govern.I think that's the situation we're inwith consciousness.If you can't explain consciousnessin terms of the existing fundamentals —space, time, mass, charge —then as a matter of logic,
you need to expand the list.The natural thing to do is to postulateconsciousness itself as something fundamental,a fundamental building block of nature.This doesn't mean you suddenly
can't do science with it.This opens up the way for you to do science with it.What we then need is to studythe fundamental laws governing consciousness,the laws that connect consciousnessto other fundamentals: space, time, mass,physical processes.Physicists sometimes saythat we want fundamental laws so simplethat we could write them on the front of a t-shirt.Well I think something like that is the situationwe're in with consciousness.We want to find fundamental laws so simplewe could write them on the front of a t-shirt.We don't know what those laws are yet,but that's what we're after.

11:34
The second crazy ideais that consciousness might be universal.Every system might have some degreeof consciousness.This view is sometimes called panpsychism:pan for all, psych for mind,every system is conscious,not just humans, dogs, mice, flies,but even Rob Knight's microbes,elementary particles.Even a photon has some degree of consciousness.The idea is not that photons are intelligentor thinking.It's not that a photonis wracked with angstbecause it's thinking, "Aww, I'm always
buzzing around near the speed of light.I never get to slow down and smell the roses."No, not like that.But the thought is maybe photons might havesome element of raw, subjective feeling,some primitive precursor to consciousness.

12:32
This may sound a bit kooky to you.I mean, why would anyone think such a crazy thing?Some motivation comes from the first crazy idea,that consciousness is fundamental.If it's fundamental, like space and time and mass,it's natural to suppose that it might be universal too,the way they are.It's also worth noting that although the ideaseems counterintuitive to us,it's much less counterintuitive to peoplefrom different cultures,where the human mind is seen as much morecontinuous with nature.

13:30
A really exciting thing is in recent yearsa neuroscientist, Giulio Tononi,has taken this kind of theoryand developed it rigorouslywith a mathematical theory.He has a mathematical measureof information integrationwhich he calls phi,measuring the amount of informationintegrated in a system.And he supposes that phi goes alongwith consciousness.So in a human brain,incredibly large amount of information integration,high degree of phi,a whole lot of consciousness.In a mouse, medium degree
of information integration,still pretty significant,pretty serious amount of consciousness.But as you go down to worms,microbes, particles,the amount of phi falls off.The amount of information integration falls off,but it's still non-zero.On Tononi's theory,there's still going to be a non-zero degreeof consciousness.In effect, he's proposing a fundamental lawof consciousness: high phi, high consciousness.Now, I don't know if this theory is right,but it's actually perhaps the leading theory right nowin the science of consciousness,and it's been used to integrate a whole rangeof scientific data,and it does have a nice property
that it is in fact simple enoughyou can write it on the front of a t-shirt.

14:48
Another final motivation is thatpanpsychism might help us to integrateconsciousness into the physical world.Physicists and philosophers have often observedthat physics is curiously abstract.It describes the structure of realityusing a bunch of equations,but it doesn't tell us about the realitythat underlies it.As Stephen Hawking puts it,what puts the fire into the equations?Well, on the panpsychist view,you can leave the equations of physics as they are,but you can take them to be describingthe flux of consciousness.That's what physics really is ultimately doing,describing the flux of consciousness.On this view, it's consciousnessthat puts the fire into the equations.On that view, consciousness doesn't dangleoutside the physical worldas some kind of extra.It's there right at its heart.

15:43
This view, I think, the panpsychist view,has the potential to transfigure our relationshipto nature,and it may have some pretty serious socialand ethical consequences.Some of these may be counterintuitive.I used to think I shouldn't eat anythingwhich is conscious,so therefore I should be vegetarian.Now, if you're a panpsychist and you take that view,you're going to go very hungry.So I think when you think about it,this tends to transfigure your views,whereas what matters for ethical purposesand moral considerations,not so much the fact of consciousness,but the degree and the complexity of consciousness.

16:26
It's also natural to ask about consciousnessin other systems, like computers.What about the artificially intelligent systemin the movie "Her," Samantha?Is she conscious?Well, if you take the informational,panpsychist view,she certainly has complicated information processingand integration,so the answer is very likely yes, she is conscious.If that's right, it raises pretty seriousethical issues about both the ethicsof developing intelligent computer systemsand the ethics of turning them off.

16:59
Finally, you might ask about the consciousnessof whole groups,the planet.Does Canada have its own consciousness?Or at a more local level,does an integrated grouplike the audience at a TED conference,are we right now having a
collective TED consciousness,an inner moviefor this collective TED groupwhich is distinct from the inner moviesof each of our parts?I don't know the answer to that question,but I think it's at least oneworth taking seriously.

17:31
Okay, so this panpsychist vision,it is a radical one,and I don't know that it's correct.I'm actually more confident aboutthe first crazy idea,that consciousness is fundamental,than about the second one,that it's universal.I mean, the view raises any number of questions,has any number of challenges,like how do those little bitsof consciousness add upto the kind of complex consciousnesswe know and love.If we can answer those questions,then I think we're going to be well on our wayto a serious theory of consciousness.If not, well, this is the hardest problem perhapsin science and philosophy.We can't expect to solve it overnight.But I do think we're going to figure it out eventually.Understanding consciousness is a real key, I think,both to understanding the universeand to understanding ourselves.It may just take the right crazy idea.